Many electronic systems operate according to quadrature clock signals having 90-degree phase differences to improve efficiency. In one example, a digital system samples data and processes the sampled data according to a frequency of a clock signal. Operating a digital system according to quadrature clock signals enables improvement in a data rate, a signal to noise ratio, or an eye diagram. In another example, a communication system upconverts or downconverts an electrical signal onto quadrature clock signals (also referred to as “quadrature carrier signals”). Employing quadrature clock signals allows communication through a single side band rather than a double side band, thus allowing conservation of bandwidth.
Operating performance of an electronic system employing quadrature clock signals depends on an accuracy of phases of the quadrature clock signals. For example, phase errors of quadrature clock signals reduce a signal to noise ratio or an eye diagram of a digital system. For another example, phase errors of quadrature clock signals of a communication system reduce suppression of spectral components at an unintended sideband. However, generating high speed (e.g., over 10 GHz) clock signals with accurate phases is challenging.
The details of various embodiments of the methods and systems are set forth in the accompanying drawings and the description below.